The records in the linkage system are derived from a number of core sets including morbidity, mortality, midwives, birth, cancer, mental health, emergency and the electoral roll. Event-based sets, such as morbidity or emergency, can feature more than one record for an individual, but other registry-based sets, such as cancer or mental health, can have only a single record per person.
As at April 30th 2012:
Linkage System
- The total number of records: 36,089,458
- Total number of chains: 3,648,842
- Maximum number of linked records in a chain: 4,214
- Average chain length (excluding single record chains): 10.5 records
Core Data Sets
- Hospital Separations
20,229,610 records (M 9,237,105, F 10,992,480) - Cancer Registrations
285,950 records (M 140,643, F 144,282) - Midwives Notifications
824,277 records (M 422,873, F 401,357) - Mental Health Contacts
434,127 records (M 199,280, F 234,768) - Death Registrations
425,183 records (M 233,600, F 191,540) - Birth Registrations
1,460,707 records (M 750,518, F 710,125) - Electoral Roll Records
2,014,679 records (M 998,601, F 1,019,622) - Emergency Presentations
10,109,544 records (M 5,243,302, F 4,865,000)
Note: singletons (people who only have one record in their 'chain' are not included) in the total number of chains.